Intersecting device for sewing machines

ABSTRACT

An intersecting device for sewing machines for intersecting the edges of a workpiece at a right angle to the feeding direction and in predetermined intervals during sewing by means of a reciprocating blade. Means are provided for disconnecting the blade during the operation, in the starting position of the sewing machine or for disconnecting the blade during sewing with a reverse feed. The device is provided with a permanently vertically displaceable blade which can be forced into engagement with a counterknife by means of a driven control disk having control paths and determining the cutting intervals.

[22 Filed:

United States Patent Landwehr [54] INTERSECTING DEVICE FOR SEWING MACHINES [72] Inventor: Giinter Landwehr, Sennestadt, Germany [73] Assignee: Kochs Adler AG, Bielefeld, Germany Oct. 13, 1970 211 App]. No.: 80,285

[30] Foreign Application Priority Data 1 Oct. 15, 1969 Germany... ..P 19 51 845.7

' 52 US. Cl ..112/130, 112/203 [51] Int. Cl. ..D05b 37/04, D05b 27/22 [58] Field of Search ..112/122, 123, 125, 130, 203

[56] References Cited UNITED STATES PATENTS 1,956,677 5/1934 Gruman ..1 12/122 1 51 Oct. 10,1972

2,363,713 11/1944 Weissenberg ..1 12/123 3,176,640 4/ 1965 Marforio ..1 12/123 3,074,363 l/1963 Gross et a1 ..1 12/125 Primary Examiner-H. Hampton Hunter Attorney-Jacob L. Kollin [57] ABSTRACT An intersecting device for sewing machines for intersecting the edges of a workpiece at a right angle to the feeding direction and in predetermined intervals during sewing by means of a reciprocating blade. Means are provided for disconnecting the blade during the operation, in the starting position of the sewing machine or for disconnecting the blade during sewing with a reverse'feed. The device is provided with a permanently vertically displaceable blade which can be forced into engagement with a counterknife by means of a driven control disk having control paths and determining the cutting intervals.

9 Claims, 9 Drawing figures INTERSECTING DEVICE FOR SEWING MACHINES BACKGROUND OF THE INVENTION range of the roundings and that with a number of cuts 0 dicular with the feed direction of the workpiece for intersecting the edges.

Partially these devices are also provided with means for stopping the operation of the cutter manually, for example, in the when interlocking the seam end by reversing the feed direction. It is also possible to change the cutting length and the cutting interval. However, these known devices are relatively complicated with regard to their attendence.

It is therefore an object of this invention to provide an intersecting device for sewing machines which is provided with simple and easily operable means controllable by the operator, for rendering the cutting means operative or inoperative at will.

It is a further object of this invention to provide an intersecting device in which the cutting means are actuated in such a manner as to leave the upper surface of the sewing machine bed plate clear for operating purposes.

Another object of this invention is to provide readily operable adjusting means for changing the intersecting intervals during sewing or in the starting position of the sewing machine.

A further object of this invention is to provide instantaneous operating means for rendering the cutting blade inoperative in the event of sewing in a reverse direction.

Still another object of this invention is to provide simple operable engaging and disengaging means for lifting the blade into a raised position, in order to prevent the operating of the blade when sewing a straight seam and to engage the blade if required.

SUMMARY These objects are attained in accordance with the present invention, with an intersecting device which includes a reciprocating blade mounted at a right angle to the feeding direction of the workpiece, driving means for actuating the blade, a stationary counterknife for cooperating with the blade in dependence on the position of the needle bar of the sewing machine which is provided with conventional stitch forming means, means for forcing the blade into engagement with the counterknife, means for varying the cutting intervals and disconnecting the blade during the operation or in the starting position of the sewing machine, and means cooperating with the means for varying the intersecting intervals and adjustable means for controlling the direction of feed, for disconnecting the blade during sewing with a reverse feed.

The various features and advantages of this invention will be apparent from the following description of an embodiment thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a sewing machine provided with the intersecting device according to the invention, showing the intersecting device in operating position; H

FIG. 2 is a right side elevational view of the sewing machine;

FIG. 3 is a partial view of FIG. 1 showing the blade in a disengaged position;

FIG. 4 is a partial right side elevation on an enlarged scale;

FIG. 5 is a view as per arrow V of FIG. 1 or the control disk;

FIG. 6 is a sectional view through the control disk taken along the line VI-VI of FIG. 5;

FIG. 7 is a perspective top plan of the throat plate of the sewing machine and a part of the device, on an enlarged scale;

FIG. 8 is a perspective top plan view of the control disk and the coupling mechanism partly in section, on an enlarged scale; and

FIG. 9 is a section taken along line IXIX of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT The sewing machine illustrated in FIGS. 1 and 2 of the drawings comprises a bed plate I, a hollow standard 2, an overhanging arm 3 and a head 4.

In the arm 3 there is pivoted a rotary drive shaft 5 for driving the needle bar 7 carrying a needle 6. Secured to the free end of the drive shaft 5 is a combined hand wheel and pulley 8 which is in driving connection with a motor, not further shown, by means of a belt 9.

In the hollow standard 2 there is arranged an adjustable lever 10 for controlling the stitch length and the direction of feed (FIG. 4) which is pivoted about a bolt 11 and has a nose l3 adjustable by means of a rotary knob 12.

The nose 13, having its fulcrum at 14, is rotatably secured to the adjustable lever 10. A lever 16 secured to a stitch regulating shaft 17 rests against the nose 13, biased a spring 15. The stitch regulating shaft 17 cooperates with the feed dog, in order to control the stitch length and the forward and reverse feed motions of the feed dog. Secured to at the lever 16 is a traverse 18 which is connected with a pedal 19 (FIG. 1) for operating the stitch regulating shaft 17 independent of the adjustable lever 10 by means of the pedal as will be described in detail later on.

As shown in FIG. 7, a throat plate 20 is secured to the bed plate 1 by means of screws 21. The throat plate 20 is provided with a stitch hole 22, an opening 23 for the passage of the feed dog (not shown) and a further opening 24 which extends essentially perpendicular to the feed direction, and into which projects a counterknife 25. This is received in a dovetailed groove 26 situated angularly to the feed direction within the throat plate 20, and fastened by means of a disk 27 having a beveling 28 and a screw 29 (FIG. 9).

A blade 30 secured to a block 31 (FIGS. 1 and 7) cooperates with the counterknife 25. The block 31 is vertically reciprocable and supported upon a vertical rod 32 screwed in the head 4, and is provided with a rearwardly projecting arm 33. This arm 33 is provided with a slot 34 engaging a slide bar 35, which is screwed into the head f the sewing machine.

Secured to the arm 3 of the sewing machine is a bearing block 36 to which is secured a bolt 37. A lever 40 having two arms 38, 39 is pivoted about the bolt 37. Slidably supported upon the arm 38 is a slide part 41 which is connected with the block 31 by means of transmission rods 42. The arm 39 is in driving connection with the drive shaft 5 by means of an eccentric 43 secured to the drive shaft 5, aconnecting rod 44 and a ball joint 45 on the arm 39. A tension spring 46 is mounted between the slide part 41 and the connecting rod 44.

Two links 47 connect the slide part 41 with a coupling part 48 which is rotatably supported by an axle 50 (FIG. 7) in a bearing member 49 arranged at the arm 3 of the sewing machine. At both ends of a bolt 51, bridging a forked part 52 of-the coupling part 48, are engaged tension springs 53 (FIGS. 7, 8), the free ends of which act on the pins 55 (FIG. 1).

Screwed to an operating rod 57, which is under the tension of a spring 56, is a cam follower 58 provided with a recess (FIG. 8) which surrounds the bolt 51 on a section of its circumference. The other end of the operating rod 57 is slidably guided in a sleeve 60 within the hollow standard 2, and carries a loose roller 61 (FIGS. 4 and 8) resting against the curve-shaped elevations of a control disk 62 under the tension of the tension springs 53.

The sleeve 60 is inserted in a double-armed hand lever 63 pivoted about a shoulder stud 64 threaded into the standard. In a recess 65 (FIG. 4) or the hand lever 63, a tie rod 66 and an adjustable stop finger 67 are rotatably hinged about a bolt 68. The stop finger 67 rests against a stud bolt 70 under the tension of a tension spring 69. The studbolt 70'is received in the hand lever 63 and can be axially displaced by means of a setting device 71. The setting device 71 consists ofa rotary knob 72 which is pivoted about a pin 73secured to the hand lever 63 and provided with a controlsurface 75 against which the stud bolt 70 rests under the tension of the spring 69.The control surface 75 causes the deviation of the adjustable stop finger 67 by means of the stud bolt 70 when turning the rotary knob 72 through 180.Aspring-loaded ball 76 serves to keep the rotary knob 72 in the determined position.

Secured to the standard 2, by means of screws 78, is a carrier 77 78 which is formed with a recess 77 for the passage of the tie rod 66 and the adjustable stop finger 67, in case the latter is deflected by means of the setting device 71. The upper edge of the carrier 77 serves as a back stop for the adjustable stop finger 67, if the same is adjusted as shown in dotted lines in FIG. 4. Furthermore, the carrier 77 serves to support the control disk 62, which is driven by a toothed gear belt pulley'8l, mounted between the standard 2 and the hand wheel 8 and secured to the drive shaft 5, at a speed ratio of four to one, by means of a toothed belt 80 (FIGS. 1, 2 and 8).

The control disk 62 rotates in ball bearings 82, 83, in which are received an axle 84 secured to the carrier 77. The disk 62 is provided with a control member essentially consisting of a disk-shaped base 86 having beveled edges about the periphery and cam-contoured projections 87 and 88, which are located at the diskshaped base 86, and have a progressively ascending curve to a maximum value (as shown in the sectional plane in FIG. 6) and a progressive descent toward the end of the curve. The cam-contoured projections 87, 88, also beveled at the peripheral lines, have different overall dimensions, as shown in FIG. 5, so that a circular path indicated by EM, is disposed on the preponderant part of the sector of the dial within the diskshaped base 86, and the smaller sector within the area of the cam-contoured projection 87. However, a circular path indicated by BI, is disposed within the area of the cam-contoured projection 87 and the projection 88, twice within the disk-shaped foundation 86.

In contrast, a circular path, which neither touches the cam-contoured projection 87 nor the projection 88, is likewise shown in FIGS. 5 and 6 and is denoted by BA.

It is apparent that, if the roller 61 of the operating rod 57 biased by the spring 56, is brought into the circular path BA, the roller 61 is forced against the internal front wall of the control disk 62, and since the front wall has a plane surface, solely the roller 61 is driven. However, no axial movements are imparted to the operating rod 57 during the rotation of the control disk 62.

The roller 61 brought into the circular path BM,is

influenced by the variationsof the control member surface 86, whichaffect the roller 61 during the rotation of the control disk 62, so that after one revolution of the control disk 62 or, since the latter is driven at a reduction ratio of four to one, after four revolutions of the hand wheel 8, the roller 61 and thus the operating rod 57 effect a maximal amplitude when the maximal projection within the cam-contoured projection 87 arrives in the area of the roller 61.

Analogously, two maximal amplitudes per revolution of the control disk 62 or two revolutions. of the hand wheel 8, are effected when the roller 61 is brought into the circular path BI.

The control member 86 is secured to the control disk 62 by means of screws 85.

As shown in FIGS. 1 and 2, the tie rod 66 has a ball pivot 89 to which is connected a thrust rod 90, the free end of which extends into a cylinder 91 and carries a guide piston 92. Between the upper covering 93 of the cylinder 92 and the ball pivot 89 there is provided a pressure spring 94. Secured to the lower part of the cylinder 91 is a pedal rod 95, the free end of which is connected with the pedal 19 by means of a ball pivot 96. Secured to the cylinder 91 is a clamping part 97 to which is hinged a further cylinder 98, the piston rod 99 of which is hinged to the traverse 18 by means of a ball pivot 100 for actuating the stitch regulating shaft 17.

As shown in FIG. 4, the tie rod 66 is connected with a lever 101 serving as a guide and rotatably secured to the standard 2 about a screw 102. Furthermore, between the tie rod 66 and the standard 2 there is provided an annular spring 103 biasing the rest of the hand lever 63 in the selected position during operation.

' ing of the drive belt 106 (FIG. 2).

In a cowling 107 (FIG. 1) there is arranged a disengaging device 108 (FIG. 8) for disconnecting the coupling element 58 from the bolt 51 fastened in the coupling part 48. For that purpose, the disengaging device 108 is provided with a cylindrical member 110 located in the cowling 107, and rotatable against the tension of a spring 109. The cylindrical member 110 is formed with a central surface part 111 located above the coupling part 58.

On the head 4 of the sewing machine there is arranged a coupling mechanism 112, for coupling the coupling element 58 to the bolt 51 of the coupling part 48. This mechanism consists of a hand lever 113 for actuating a shaft 114 (FIG. 1) carrying a finger 115, which acts upon the arm 33 of the block 31 when operated, and presses the blade 30 downwards.

The operation of the device is as follows:

It will be assumed that the sewing machine and the intersecting device are in a position as shown in FIG. 1:

During the rotation of the hand wheel 8 and the drive shaft 5, the needle bar 7 moves up and down. The motions derived from the eccentric 43 are transmitted via the connecting rod 44 to the arm 39 of the doublearmed lever 40 and from here passed on via the arm 38, the slide part 41 slidably received on the arm 38, and the transmission rods 42 to the block 31, which carries the blade 30. Both the needle bar 7 and the blade 30 perform their downward motions when the feed of the workpiece is interrupted.

Moreover, supposing that the hand lever 63 carrying the setting device 71, is in position as shown in FIG. 4, in which the loose roller 61 is within the circular path BA:

As stated above, in this case no axial movements are transmitted to the operating rod 57, since the roller 61 rests against the plane internal front wall of the control disk 62. Accordingly, no motion is transmitted to the coupling part 48, which is adapted to vibrate about the axle 50, the bolt 51, the links 47, the slide part 41, the transmission rods 42 and the block 31. Thus, the blade remains out of engagement with the counterknife 25, although, due to the activity of the eccentric 43 and the non-interrupted transmitting means, the blade 30 moves up and down, and a passage for the workpiece likewise remains between the blade .30 and the counterknife 25 if the blade 30 is in its bottom dead center.

This method of using the intersecting device is required when the workpiece is not to be intersected, which, for example, happens when sewing straight seams by sections, or, when securing the end of a seam, which can be done in a known manner by operating the adjustable lever for controlling the stitch length and the direction of feed or by means of the pedal 19, as described later on.

When using the sewing machine only for sewing operations requiring no intersection of the workpiece edges, the blade 30 can be brought into a still higher position, which is less hindering to the operator during sewing. This is effected by actuating the disengaging device 108. On turning the cylindrical member 110 (FIG. 8), the control surface-part 111 located above the coupling element 58, with only a little space therebetween, the latter is pressed downwards and causes the recess 59 to disengage from the bolt 51 of the coupling part. Due to the effect of the tension springs 53 and 54, the slide part 41 on the arm 38 F IG. 3) is moved, until it rests against the member 40, thus moving the block 31, slidable on the vertical rod 32, by

means of the transmission rods 42, and lifting also the blade 30 somewhat more. Upon rotation of the drive shaft 5, due to the displacement of the slide part 41 into the proximity of the acis of rotation, but keeping the same lift on the driving side, the blade 30 performs a smaller lifting motion than prior to the uncoupling of the operating rod 57. After uncoupling, due to the spring 56 (FIG. 3), the coupling element 58 rests without effect against the bolt 51. y

In order to bring the blade 30 into the first position (FIG. 1), the coupling mechanism 112 has to be actuated (FIG. 1 and 7). This is done by pressing down the hand lever 113 so that, via the finger and the rearwardly projecting arm 33, the block 31 and thus the blade 30 are moved downwards. Thus the recess 59 of the coupling element 58 can engage the bolt 51 under the tension of the spring 56, so that the operating rod 57 is again in operative connection with the blade 30 (FIG. 1).

Now, supposing that the operator has to sew workpieces having edges, which are intersected after four stitches formed by the needle.

For this purpose, first of all the rotary knob 72 (FIG. 4) of the setting device 71 is set to number 4 (FIG. 8). Thus, the adjustable stop finger 67 pivoted about the bolt 68 and under tension of the spring 69, abuts against the stud bolt 70, which is received in the hand lever 63 with axial movement and consequently abuts against that part of the control surface 75 of the rotary knob 72, in which the circular countersinking takes its lowermost course.

When moving the hand lever 63 upwards into the position shown by dotted line (FIG. 4), the stop finger 67 rests against the upper edge of the carrier, which serves as a back stop. During this motion of the hand lever 63, the roller 61 arrives at the control member surface 86 and consequently out of the circular path BA into the circular path BM, which occurs by sliding the roller 61 upwards on the beveled edges, located about the periphery of the disk-shaped base 86.

As already described above, in this case, the operating rod 57 and the blade 30 perform one up and down motion per four stitches of the needle 6.

When one cut of the blade 30 after each second stitch of the needle 6 is desired, the rotary knob 72 of the setting device 71 has to be turned about to the number 2 (FIG. 8), causing in the part of the control surface 75 of the knob 72, in which the circular countersinking has a maximum value, stud bolt 70 to deflect the stop finger 67 in such a manner, that after actuating the hand lever 69 the stop finger 67 can not abut against the upper edge of the carrier 77, but will enter the recess 79 of the carrier 72 in order to allow an additional deflection of the hand lever 63 and thus bring the roller 61 into the circular path BI. With the roller 61 in the path BI, the operating rod 57 performs one maximal amplitude per two stitches of the needle 6 and consequently, also the blade 30 performs one cut per two stitches of the needle 6.

The deflection of the described above, from the circular path BA to the circular path BM or, after corresponding adjustment of the knob 72, to the circular path Bl by actuating the hand lever 63, can also be achieved by means of the pedal 19 (FIG. 1

The pedal plate indicated at 19 in FIG. 1, can be deflected about a certain sector of dial by means of a foot, so that the pedal rod 95 can act like a pull rod or a pressing rod.

When it acts like a pull rod, the hand lever 63in the position shown in dotted lines (FIG. 4) is deflectedinto the position drawn in solid lines (FIGS. 1, 2'and 4). This takes place in such a manner, that during lifting of the cylinder 9],which is secured to the pedal rod 95, by means of the pressure spring 94, the ball pivot 89 and the tie rod 66, the hand lever 63 is deflected in such a manner, that the roller 61 lies in the circular path BA, in which the blade 30 is out of engagement with the counterknife 25.

During lifting of the cylinder 91, the cylinder 98 secured to the pedal rod 95, is also moved upwards. Thus, the piston rod 99 (FIG. 1) of the cylinder 98 after being supported on the inner bottom of the cylinder 98, has deflected the traverse18 and thus also the stitch regulating shaft 17 for sewing with a reverse feed, against the bias of the tension spring 15.

When moving the pedal rod 95 downwards, the tension spring causes the deflection of the traverse l8 and the movement of the stitch regulating shaft 17 into their normal forward feed positions. Simultaneously, the piston rod 92 of the thrust rod 90 abuts against the upper covering 93, whereby the thrust rod 90 is moved downwards, thus deflecting the hand lever 63 by means of the tie rod 66, in order to bring the roller 61 into the circular path BM or BI, depending on the adjustment of the stop finger 67.

What I claim is:

1. in a sewing machine having a bed plate, a throat plate on said bed plate, a hollow standard, an overhanging arm, a head, a rotary drive shaft extending longitudinally in said arm, a combined hand wheel and pulley secured to said drive shaft, a reciprocating needle bar driven by said shaft, stitch forming means, and adjusting means for controlling the stitch length and the feed direction, means for intersecting the edges of a workpiece in predetermined intervals during sewing, comprising a blade mounted at right angles with the sewing direction, a stationary counterknife cooperating with said blade, driving means for imparting up and down motions to said blade as a function of the positions of said needle bar, engagement means for forcing said blade into engagement with said stationary counterknife, means for varying the cutting intervals by disconnecting said blade during the operation and in starting position of said sewing machine, and means cooperating with said means forvarying the cutting intervals and said adjusting means for controlling the stitch length and the feed direction, for disconnecting said blade during sewing with a reverse feed.

2. In a sewing machine as set forth in claim 1, said driving means for imparting up and down motions to said blade comprising, eccentric means mounted on said rotary drive shaft, a double-armed lever pivoted below said overhanging arm, a connecting rod linked to said eccentric means and one arm of said double-armed ment with said counterknife comprising a driven con-- trol disk follower means thereon displaceable in at least two selective control paths (BA, BM, BI), and an operating rod between said control disk and said driving means for imparting up and down motions to said blade, for engaging and disengaging said blade with or from said stationary counterknife.

4. ln a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk follower means thereon displaceable in at least two selectively acting control paths (BA, BM, BI), an operating rod between said control disk and said driving meansfor imparting up and down motions to said blade, said follower means secured to one end of said operating rod, and disengaging means between said driving means and the other end of said operating rod, said means forvarying the cutting interval or disconnecting said blade during the operation or in starting position of said sewing machine comprising a hand lever connected with said follower means for moving the same into one of said control paths (BA,BM,BI) of said driven control disk.

5. In a sewing machine as set forth in claim 4, said hand lever connected with'said follower means comprising a setting device for defining the field of traverse of said hand lever connectedwith said follower means.

6. In a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk follower means thereon displaceable in selective control paths, an operating rod between said control disk and said driving means for imparting up and down motions to said blade, said a follower means secured toone end of said operating rod and acting in one of said control paths, and a hand lever connected with said follower means for moving the same into one of said control paths of. said driven control disk, said means cooperating with said means for varying the cutting intervals and said adjusting means for controlling the stitch length and the feed direction, for disconnecting said blade during sewing with a reverse feed, comprising a-pedal, a tie rod linked to said hand lever, and a linkage operable by means of said pedal and in operative connection with said tie rod and said adjusting means for controlling the feed direction and causing a movement of said follower means out of said control paths of said control disk and subsequently the engaging of said means for controlling the reverse feed when said pedal is actuated.

7.v In a sewing machine as set forth in claim 5, said setting device for defining the field of traverse of said hand lever connected with said follower means comprising an adjustable stop finger pivoted to said hand lever, a stop means situated in the path of motion of said stop finger, a rotary knob pivoted to said hand lever and having a control surface, a stud bolt slidably received in said hand leverand disposed between said stop finger and said control surface, a tension spring disposed between said stop finger and said hand lever, and an adjusting means for said rotary knob.

operable cylinder having a control surface part cooperating with said coupling element when actuated, for causing a disconnection of said coupling element from said bolt, and tension spring means for moving said blade into a raised position after disconnection of said coupling element from said bolt, and a coupling mechanism for coupling said coupling element with said bolt, comprising a'second hand lever, a shaft actuated by said second hand lever, and a finger secured to said shaft bearing upon said driving means to cause the I interlocking of said coupling element with said bolt.

9. In a sewing machine as set forth in claim 3, v wherein said driven control disk having selectively act- I ing control paths is provided with a gear tooth system, a gear toothed belt pulley secured to said rotary drive shaft and arranged between said combined hand wheel and pulley and said standard, and a toothed belt forming a driving connection between said belt pulley and said control disk. 

1. In a sewing machine having a bed plate, a throat plate on said bed plate, a hollow standard, an overhanging arm, a head, a rotary drive shaft extending longitudinally in said arm, a combined hand wheel and pulley secured to said drive shaft, a reciprocating needle bar driven by said shaft, stitch forming means, and adjusting means for controlling the stitch length and the feed direction, means for intersecting the edges of a workpiece in predetermined intervals during sewing, comprising a blade mounted at right angles with the sewing direction, a stationary counterknife cooperating with said blade, driving means for imparting up and down motions to said blade as a function of the positions of said needle bar, engagement means for forcing said blade into engagement with said stationary counterknife, means for varying the cutting intervals by disconnecting said blade during the operation and in starting position of said sewing machine, and means cooperating with said means for varying the cutting intervals and said adjusting means for controlling the stitch length and the feed direction, for disconnecting said blade during sewing with a reverse feed.
 2. In a sewing machine as set forth in claim 1, said driving means for imparting up and down motions to said blade comprising eccentric means mounted on said rotary drive shaft, a double-armed lever pivoted below said overhanging arm, a connecting rod linked to Said eccentric means and one arm of said double-armed lever, a block carrying said blade, a vertical rod receiving said block, and a transmission rod linked to said block and the free arm of said double-armed lever.
 3. In a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk follower means thereon displaceable in at least two selective control paths (BA, BM, BI), and an operating rod between said control disk and said driving means for imparting up and down motions to said blade, for engaging and disengaging said blade with or from said stationary counterknife.
 4. In a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk follower means thereon displaceable in at least two selectively acting control paths (BA, BM, BI), an operating rod between said control disk and said driving means for imparting up and down motions to said blade, said follower means secured to one end of said operating rod, and disengaging means between said driving means and the other end of said operating rod, said means for varying the cutting interval or disconnecting said blade during the operation or in starting position of said sewing machine comprising a hand lever connected with said follower means for moving the same into one of said control paths (BA,BM,BI) of said driven control disk.
 5. In a sewing machine as set forth in claim 4, said hand lever connected with said follower means comprising a setting device for defining the field of traverse of said hand lever connected with said follower means.
 6. In a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk follower means thereon displaceable in selective control paths, an operating rod between said control disk and said driving means for imparting up and down motions to said blade, said a follower means secured to one end of said operating rod and acting in one of said control paths, and a hand lever connected with said follower means for moving the same into one of said control paths of said driven control disk, said means cooperating with said means for varying the cutting intervals and said adjusting means for controlling the stitch length and the feed direction, for disconnecting said blade during sewing with a reverse feed, comprising a pedal, a tie rod linked to said hand lever, and a linkage operable by means of said pedal and in operative connection with said tie rod and said adjusting means for controlling the feed direction and causing a movement of said follower means out of said control paths of said control disk and subsequently the engaging of said means for controlling the reverse feed when said pedal is actuated.
 7. In a sewing machine as set forth in claim 5, said setting device for defining the field of traverse of said hand lever connected with said follower means comprising an adjustable stop finger pivoted to said hand lever, a stop means situated in the path of motion of said stop finger, a rotary knob pivoted to said hand lever and having a control surface, a stud bolt slidably received in said hand lever and disposed between said stop finger and said control surface, a tension spring disposed between said stop finger and said hand lever, and an adjusting means for said rotary knob.
 8. In a sewing machine as set forth in claim 1, said engagement means for forcing said blade into engagement with said counterknife comprising a driven control disk having selectively acting control paths, an operating rod between said control disk and said driving means for imparting up and down motions to said blade, a disengaging device between said driving means and said operating rod having a bolt mounted on said driving means, a coupling element secured to said operating rod and provided with a recess surroUnding said bolt on a section of its circumference, a hand-operable cylinder having a control surface part cooperating with said coupling element when actuated, for causing a disconnection of said coupling element from said bolt, and tension spring means for moving said blade into a raised position after disconnection of said coupling element from said bolt, and a coupling mechanism for coupling said coupling element with said bolt, comprising a second hand lever, a shaft actuated by said second hand lever, and a finger secured to said shaft bearing upon said driving means to cause the interlocking of said coupling element with said bolt.
 9. In a sewing machine as set forth in claim 3, wherein said driven control disk having selectively acting control paths is provided with a gear tooth system, a gear toothed belt pulley secured to said rotary drive shaft and arranged between said combined hand wheel and pulley and said standard, and a toothed belt forming a driving connection between said belt pulley and said control disk. 